On this week's show Alok Jha interviews Professor Steven Pinker about his new book The Better Angels of Our Nature. Alok asks Pinker about the statistical analysis that informs his conclusions that, overall, levels of violence have decreased as human civilisation has progressed. Pinker also relates his argument to the latest discoveries about the neuroscience of violence.

Also on this week's show, we look into a scientific demonstration of a phenomenon that had Star Wars fans and sci-fi geeks around the world gazing in wonder: quantum levitation. Dr Boaz Almogof Tel Aviv University explains the novel effects of very low temperature on superconductors in magnetic fields and how we could use this phenomenon in future technologies.